An important step in the manufacture of integrated circuit is testing the packaged integrated circuit device prior to shipment to a customer. In the production of integrated circuits, it is important not only to determine whether a completed integrated circuit package is functioning properly, but to be able to test the integrated circuit packages at as low a cost as possible. Accordingly, any steps to improve the quality of and reduce the cost of testing integrated circuit packages are beneficial. The production testing of integrated circuit packages is performed using automated equipment such as handlers that load each of the devices into contactors or sockets on test boards, and then sort them based on the results. These sockets are designed to provide connections between the integrated circuit package and a Printed Circuit Board (PCB), and may comprise both a mechanical and electrical element. Further, as in selecting any component of a high volume test system for integrated circuit packages, it is important to minimize the cost of the test system. Accordingly, it is important to use standard components whenever possible to minimize the cost of testing.
Further, certain integrated circuit devices may provide different challenges during tests. For example, testing high speed devices, such data transceiver operating at high data rates, may be difficult. In particular, the additional length of the connectors/pogos of the socket may introduce noise, thereby reducing the speed at which the device may be tested. To test some of the I/O functionality in certain devices, such as data transceivers of the integrated circuit, some input and output ports of the integrated circuit device must be connected to each other. A socket for holding an integrated circuit comprises contact elements that are held in place by a package body and provide electrical connections between a packaged semiconductor device in the socket and a printed circuit board. This connection is made in conventional devices through contact elements of the socket which are connected by a conductive trace on the circuit board having the socket. However, noise generated on the contact elements of the socket may interfere with the high speed data transmission.
In some sockets, such as a socket for hosting a Ball Grid Array (BGA) package, the contact elements comprise flexible contact elements, often called pogo pins. For a BGA package having a plurality of solder balls on the bottom of the package, the mechanical aspect of the socket provides a certain amount of force to break through any oxide on the solder ball as well as provides a means to form an electrical connection. That is, in view of possible variations of solder balls of the package, flexible contact elements are provided to ensure that each contact element makes as sufficient connection to a solder ball. Accordingly, each of these contact elements has a working range or travel range which provides compensation for tolerances in the solder balls of the integrated circuit package. The contact element provides forces in both directions to make the electrical contact between a solder ball and a contact pad of the PCB. In order to provide the appropriate amount of force while maintaining the ability to compensation for the tolerances in the planarity of the package balls, it is necessary to maintain the over all length of the contact elements. Reducing the mechanical length of the contact element may impact the electrical contact between the integrated circuit device and the contact pads on the printed circuit board, and therefore affect the quality of the testing system.
Accordingly, there is a need for an improved socket for an integrated circuit and method of making a connection in a socket.